(a) Field of the Invention
The present invention relates to cylindrical locks and more particularly to a cylinder lock which comprises a movable lock barrel matching with a fixed lock barrel to form a plurality of passage ways for the insertion therein of a plurality of stepped pins of a key to control its locking and unlocking. The stepped pins of the key can be separated therefrom for keeping by different people or in different locations. An alarm device is connected to the lock to produce alarm signal when an unauthorized key or other object is used to unlock the lock.
(b) Description of the Prior Art
A conventional cylinder lock is generally comprised of a cylindrical housing having received therein a lock barrel. In the lock barrel, a plurality of tumbler pins in different size are transversely movably set to aim at a plurality of driver pins. When an authorized key is inserted in the lock barrel, the steps of the key can be turned to push the tumbler pins to drive the driver pins to turn the lock barrel to rotate so as to further drive a spring bolt to move forward or backward. One disadvantage of this type of cylinder lock is that the driver pins of the lock barrel are difficult to process and easy to break. Another disadvantage of the this type of cylinder lock is its limitation to the specification configurations.